Multispeed governor



Dec. 19, 1944. E. MARTIN ET AL MULTISPEED GOVERNOR Filed Nov.'14. 1941Patented Dec. 19,

MULTISPEED GOVERNOR Erle Martin, West Hartford, and Nelson R. Richmond,Thompsonville, Conn.,

assignors to' United Aircraft Corporation, East Hartford,

Conn., a corporation of Delaware Application November is, 194i, serialno. nales is claims. (ci. 17o-135s) This invention relates toimprovements in control means for change speed gearsfand has particularreference to an improved control for change speed gears interposedbetween a vehicle engine and an engine driven propeller.

An object of the invention resides in the provisionof an improvedcontrolof the character indicated -including means eiective to facilitate thechange from one speed to another by acting to reduce the speeddifferencebetween the driv ing' and driven gear elements di the changespeed gear.

A further object resides in the provision of a control mechanism oi thecharacter indicated operatively associated with a propeller pitchcontrolling governor to maintain a substantially constant engine speedfor" different ratios of the change speed drive.

A still further object resides in the provision of a control means ofthe character indicated operatively associated with the change speedgear in such a manner that the control means is automatically actuatedwhenever a gear change is initiated and serves to prevent an excessivechange in engine speed during shifting of the gears and particularlywhen the change speed gear mechanism is in a. neutral ornon-drivingposition.

Other objects and advantages will be more particularly pointed outhereinafter or willbecome apparent as the description proceeds.

In the accompanying drawing, in which like reference numerals are usedto designate similar parts throughout, there is illustrated, in twoslightly modied forms, a suitable mechanical embodiment for` the purposeof disclosing the invention. The drawing, however, is for the purpose ofillustration only and is not to be taken as limitingor restricting theinvention since itv lwill be apparent to those skilled in the art thatvarious changes in the illustrated embodiment means for changing thegear ratio between the engine and the propeller.' For example, it may befound desirable to operate the propeller at a very high rotational speedand relatively low pitch angle for taire-od in order to develop thenecessary tractive thrust when the airplane Ais travelling at relativelyslow speeds. As the speed of the airplane increases it is desirable tooperate the propeller ,at a slower speed relative to engine speed sothat the emciency of the engine can he maintained at a high levelwithout a serious loss in propeller emciency due to excessive blade tipvelocities. Various other reasons for 'utilizing such change speed geardrives between the engine and the propeller are known to the prior artand do not in .any way aect the scope of the invention.4 It has so farbeen found satisfactory to utilize a change speed gear mechanismproviding drives at two dierent gear ratios between the engine and thepropeller. It is to be understood, however, that drives including morethan two gear ratios may be utilized without in any way exceeding thescope of the invention.

' Referring to the drawing in detail, the numeral i@ generally indicatesa vehicle engine such as maybe used ior the propulsion of an airplaneand the numeral i2 generally indicates a controllablepitch propellerwhich may be of any suitable or desired vforni driven by the engine I0and which may be of any suitable or desired form, the propellerillustrated being oi the lgeneraltype illustrated ant-l described inUnited States application Serial No. 482,265, tiled April, 1943, by JohnE. Anderson, for Pitch changing mechanisms.

The propeller is carried upon a propeller shaft i4 projecting into thefront end of nosepiece I6 of the engine I0 and operatively connectedwith may be resorted tov without in any way exceeding the scope of theinvention. I

In the drawing,

Fig. 1 is a diagrammatic sectional view through a propeller driveincluding -a change speed gear mechanism and through a speed governorshowing the application thereto of a governor control constructedaccording to the invention, and

Fig. 2 is adiagrammatic sectional view through a. fragmentary portion ofa speed governor showing a somewhat vmodied form Aof control mechanism.constructed according to the invention. v

In certain types of modern airplanes having high maximum speed andrelatively heavy wing loading, it has been found desirable to providethe engine power shaft I8 by a suitable gea. mechanism generallyindicated at 20. i

The gear mechanism 20 may conveniently com prise an annular reactiongear element 22' rigidly secured in the engine casing and provided withtwo sets 24 and 26 of internal gearteeth, a planetary pinionl gearsystem, a drive gear 28 on the power shaft i8 and a driven gear 30 onthe propeller shaft I4'. The pinion gears, two .of which are indicatedat 32 and 34, are mounted in the ilanged iannular portion 36 of a cage38 which surrounds the propeller shaft i4 and is'provided with a piston40 reciprocable in a cylinder 42 also concentric with the propellershaft and rigidly supported by the engine casing.

Each of the pinion gears 32 has three sets of gear teeth, as indicatedat 44, 46 and 48. The

sets 44 are permanently in mesh with thev teeth' sets of teeth 48 are inmesh with the small diameter set 24 of internal gear teeth in thereaction element 20 and when the change speed gearis in neutral,disconnecting the engine from the propeller, both sets of gear teeth 46and 48 are in the space between the internal gear teeth 26 and 24 of thereaction gear element.

The planetary gears are moved from one driving position to the lother bymovement of the piston 40 induced `by the application of hydraulic fluidunder pressure to one end or the other of the cylinder 42. Hydraulicfluid under pressure is supplied through some suitable source; such asthe engine lubricating oil pump, through a pressure line 50 to a valve52 having a manual control handle 54. A drain line 56 leads from thevalve and opposite sides of the valve are connected with opposite endsof the cylinder 42 by-uid lines 58 and 60. When the handle 54 is in theoperative position illustrated, pressure iiuid is supplied to the righthand end of the cylinder 42 moving the piston 40 to its left handposition and placing the planetary gears in their low speedI drivingposiand the slip Iioint |06 having relatively rotatable parts, with thepitch changing mechanism of the propeller I2. The shaft is moved in apitch increasing direction by the application of hytion. If the handle54 is moved to the position indicated by dotted lines the high pressureiiuid will be supplied to the left hand end of the cylinder, the righthand end being simultaneously connected with the drain line 56, vand theplanetary gears will be moved to their high speed driving position. ThepistonV 40 is so dimensioned that, taking into consideration thepressure of the Iiuid in the pressure line 50, the piston does not exertsuicient force to move the planetary gears as long as power isbeingtransmitted from the accomplish a gear shift the pilot must not onlysetthe handle 54 in the position corresponding to the desired speedchange but must also reduce the engine power by retarding the throttle.As soon as the engine power has decreased to a predetermined value thepiston 40 will move and eiect the gear shift. After theindicated gearshaft I8 to the shaft I4. Therefore, in order to shift has been effectedthe throttle may be advanced to increase the engine power.

During constant speed operation the propeller pitch is controlled by aspeed governor generally indicated at 62. This governor includes arotatable shaft-64 carrying at one end the yballs 66 e and operativelyconnected at the other end to a fluid pump 68. This shaft is driven fromthe propeller shaft I4 by a suitable drivediagrammatically illustratedas including the gears 68, 10. 12 and 'I4 and the shaft 16 carrying thegears 10 and 14. The output of the pump 68 is led through a channel 18past a pressure relief valve 80 which regulates the -pump outletpressure to a port 82' in a valve casing 84 within which is areciprocable valve sleeve 86 Vthe movements of which are controlled bythe balance of forces between the flyballs 66 andthe governor speederspring 88 in a manner well known to the art. From a second port 90 inthe valve casing a fluid line 82 leads for a lower speed. When thepiston 40 is moved to one end of a cylinder 84 of aservo-motor generallyindicated at 86. Within the cylinder 84 there is a piston 88 mounted ona shaft |00 operatively connected through the links |02 and |04 draulicfluid under pressure to the piston 98 and is moved in a pitchdecreasing-direction by the compression spring |08 which becomesoperative when the iluid line 82 is connected with drain through thehollow valve sleeve 86. The sleeve 86 moves to connect the line 82 withthe pressure line 18 or with drain in accordance with governor demandsfor an increase or a decrease in the speed of the power plant includingthe engine I0 and the propeller |2.

The speed setting of the governor may be adjusted by changing theloading on the speeder spring 88. This may be accomplished by changingthe position of the mova le abutment I I0 by the pinion ||2 rotatable bys itable means such as the manually rotatable pulley I|4. Thecompression spring I I6 to a large extent balances the force of thespeeder spring 88 on the abutment |I0 and removes la large portion ofthe abutment adjusting load from the pulley II4.

Within the cylindrical movable abutment |I0 there is a second abutmentin the form of a reciprocable piston |I8 which directly receives the endof the speeder spring, and a iiuid line |20 leads to the space betweenthis piston and the closed end of the cylindrical abutment I I0. Thisuid line `|20 leads to the interior of a valve casing |22 theoppositeside of which is connected .with the pump pressure line 18 by abranch conduit |24. Within the-casing |22 there is a two position valveplunger |26 having one operative position, as illustrated, in which itconnects the fluid line |20 with drain through the branch linel |28 anddrain port |30 and a second position in which it blocks oi the drainport and connects the pressure line |24 with the fluid line |20 to admitfluidunder pressure to the space between the closed end of the abutmentI I0 and the abutment piston I I8. This valve is controlled by a piston|32 reciprocable in a cylinder |34 and urged in a direction to move thevalve plunger I 26 to drain position by a compression spring |36. Afluid line |38 is connected with the end of the cylinder |84 oppositethe valve |22 to introduce uid into the space between this end of thecylinder and the piston |32 to move thavalve plunger |26 to the.position in which it connects the line |20 with the pressure line |24.This line |88 is led into the cylinder 42 at a location such that itsend is covered by the piston 40 when the piston is in the low speed andneutral positions. ,'The piston 40 is provided in its periphery with anannular groove |40 connecting with a drain passage |42 so that the line|38 is connected with drain whenever the gear is in the low speed driveor neutral position. Since the release of pressure from the piston |32will connect the passage |20 with drain, whenever the gear 20 is in thelow speed or neutra1 position hydraulic fluid will be drained from thespace between the piston abutment ||8 and the adjustable abutment ||0allow.- ing the piston I8 to rise and reduce the load on the speederspring 88 thus setting the governor to effect a high speed vdrivingconnection in the change speed gear the iluid line |38 will be connectedwith the line 58 which will be in turn connected with the pressure line50 so that the piston |32 will be moved to position the plunger |26 toconnect the pressure line 18, 24 with the line and introduce hydraulicfluid into the space between the piston abutment ||8 and the adjustableabutment |||l.L The piston abutment ||6 will then be moved downwardlyuntil it contacts the stop |41 thus increasing the load on thespeederspring 88 and setting the governor for a higher propeller speed.

The speeder spring 86 is so selected and the position of the stop |44 sodesigned that the 'speed tothe loW speed position, promptsynchronization of the low speed drive gears is accomplished and theshifting of the gear is materially facilitated. Likewise, increasing thepropeller speed when the gear is shifted inthe op-4 posite directionalsohastens the synchronization of the high speed drive gears andfacilitates the gear shift. In addition, placing the propeller in a slowspeed high pitch condition whenever the change speed gear is in neutralwill greatly minimize the danger of the propeller seriously overspeedingby windmilling with the airplane upon which it is mounted in iiight.

The' governor 62 is provided with a compensating device in the form of apiston M5 reciprocabie.

in a cylinder M6 and connected by a rod idg and a lever |50 having afixed pivotal support at |62.,

with a pilot valve ld reciprocable in the hollow valve sleeve 66 andcontrolling the lower pori-l H56 in this valve sleeve. The piston itilis urged to a neutral position in which the pilot valve ld closes theport |58 when the flyballs 56 are intheir on-speed positionsubstantially parallel to the axis of the shaft 66 by a compressionspring l@V and is moved away from this position by the application offluid under pressure through a channel |60 leading from a cylinder` |52in the y servo-motor t@ within which is a reciprocable pismitted throughthis line moves the piston to a position determined by the limit stop|16 in which the pivot point |66 is moved upwardly ortowards the Speederspring 68. T'his movement of the pivot point |66 moves the pilot valveE54 to a position above that illustrated in Fig. 1 and at which theSpeeder spring 88 has to be further compressed before the valvesleeve 86is moved by the yballs 66 to a position in which the pilot valve closesthe port |56, which position corresponds to a higher speed setting ofthe governor. Thus, by this means the governor is placed in a lowerspeed setting when the line |36 is connected with drain and in a higherspeed setting when fluid under pressure is led through the line |38 intothe cylinder i12. Otherwise the operation ofthe mechanism is the samedescribed above in connection with Fig. l.

While a suitable mechanical embodiment in two slightly dinerent formshas been hereinabove described and illustrated in the accompanyingdrawing, for the purpose of vdisclosing the invention, it is to beunderstood `that the invention is not limited to the particularembodiment so illustrated and described, but that such changes `in thesize, shape and arrangement of the various parts may be resorted to ascome within the scope of the sub-joined claims.

Having now described the invention so that others skilled in the art mayclearly understand the same, what it is desired to secure by LettersPatent is as follows:

l. A control for a power plant including a driving device, a drivendevice, a speed responsive governor driven from said driven device andcontrolling the speed of said driven device at all times by effectingspeed varying changes in said driven device, a change speed gear betweensaid for shifting said gear, said control comprising mechanismoperatively connected with and interposed between said gear shiftingmeans and said governor for automatically providing a high speed settingfor said governor whenever said change lspeed gear is in said high speeddrive speed changedemand of the governor as expressed by the position ofthe valve sleeve 66.

In the form of the invention shown in Fig. 2,

.the pistonlabutment H8 is omitted as is the piston |32, cylinder |34,valve casing |22 and plunger |26 together with the fluid lines |20, |24and |28. The lever |50 instead of being mounted position and a low speedsettingfor said governor whenever said change speed gear is in said lowspeed drive or said neutral position.

2. The arrangement asset forth in claim l in which the differencebetween said governor speed gear between said engine and said propellerpro-A viding atleast two gear ratios and a decoupled condition betweensaid engine and said propeller, and hydraulic means for shifting saidlgear, governor adjusting meansl including hydraulic means for changingthe speed setting of said governor.

on a fixed pivotal lconnection is mounted on a movable connection |66carried bya'rod |68 secured to .a pistonl |10 reciprocable in a cylinder|12. A compression spring |14 in one end of the eynnder |12 urges thepiston no. to a umiting end of the cylinder |12 opposite thatcontainernor setting.

and means operated by said gear shifting means for controlling thehydraulic means for, changing the speed setting of the governor andincluding means for directing fluid under pressure to said governoradjusting means when said gear is in one speed ratio to establish onegovernor setting and todrain fluid from said 'governor adjusting meanswhen said gear is in another speed ratio or decoupled condition toestablish another gov- 4. The arrangement as set forth in claim`3 in ingthe spring |14 and duid underpressure ad- 75 which said governor has aspeeder spring and said hydraulic means for changing the governor speedsetting acts to vary .the loading on said speeder spring.

5. The arrangement as set forth in claim 3 in which the governor has a`speeder spring. and said hydraulic means for changing the governorspeed setting includes a cylinder at one end of said spring, a piston insaid cylinder formingV a movable abutment for said spring, a stopcarried by said cylinder at each side of said piston, and means forcontrolling the application of hydraulic fluid under pressure to saidpiston.

6. The arrangement as set forth in claim 3 including a source 'ofhydraulic fluid under pressure for said governor, a different source ofhydraulic fluid under pressure for shifting said change speed gear, aSpeeder spring for said governor, a hydraulic gear shifting mechanism,an expansible chamber device connected with said governor source ofhydraulic fluid under pressure for changing the loading on said Speederspring, a valve for controlling the application `of hydraulic fluidunder pressure to said expansible chamber device, a second expansiblechamber device for operating said valve, a fluid connection between saidsecond expansible chamber device and said gear shifting mechanism, andmeans within said gear shifting mechanism for-connecting said fluidconnectionwith said different source of hydraulic fluid under pressurewhen said gear is in a high speed \drlve position and for venting saidfluid connection to drain when said gear is in a low speed driveposition or in said decoupled condition.

7.. The arrangement .as set forth in claim 3 including a source ofhydraulic uid under pressure for said governor, a different source ofhydraulic fluid under pressure for shifting said change speed gear, aSpeeder spring for said' governor, a hydraulic gear sluiting mechanism,an expansible chamber device connected with said governor source ofhydraulic fluid under pressure forchanging the loading on said speederspring, a valve for controlling the application of hydraulic fluid underpressure -to said expansible chamber 9. The arrangement as set forth inclaim 3 including, a governor compensating pilot valve, a lever carryingsaid valve, a movable pivot for said lever, an expansible chamber devicefor moving ated means for adjusting said governor to provide a selectedengine speed, and means controlled by said shifting means for adjustingsaid governor, while maintaining the setting of said manually operatedmeans, to change the propeller speed in accordance with the change madein said transmission ratio by said shifting means.

ll. In combination with an aircraft engine and a controllable-pitchpropeller, a change speed mechanism connecting said engine and said pro^peller, shifting means for changing the speed ratio of saidtransmission, adjustable governor means driven from the propeller sideof said device, a second expansible chamber" device for operating saidvalve, a uid connection between said second expansible chamber device.and said gear shifting mechanism, and means within said gear shiftingmechanism for connecting said 'uid connectionwith said different sourceof hydraulic iluid under pressure when said gear is in a high speeddrive position and for venting said fluid connection to drain when saidgear is in' a low speed drive position or in said decoupled conditionsaidmeans within said gear shifting mechanism comprising a gear shiftingpiston having a drain channel leading from the periphery thereof anddimensioned to cover the end of said fluid connection when said gear isin its low speed position or its decoupled condition.

8. The arrangement as set forth in claim 3 in which said governor has vacompensating pilot valve and said hydmulic means for changing thelgovernor speed setting acts to change the position of said pilot valve.

change speed mechanism for controlling the speed of said propeller bycontrolling the pitch thereof, manually operated means for adjusting thespeed setting of said gvernor, and means controlled by said shiftingmeans for additionally adjusting the speed setting of said governor whenthe speed ratio of the transmission is changed. whereby the propellerspeed is always controlled and the engine speed is maintained atsubstantially the same selected value for different speed ratioskof saidtransmission.

l2. A control for a power plant includinga driving device, acontrollable-pitch propeller driven thereby, a speed responsive governordriven by said propeller and controlling the speed of said propeller atall times by effecting changes in thefpropeller pitch, a change speedgear between said driving and driven devices having a high speed driveposition, a low speed drive position and a neutral position, andmanually actuatable means for shifting said gear, said'controlcomprising mechanism actuated only on shifting of said gear andoperatively connected with and interposed between said gear shiftingmeans and said governor for automatically providing a high speedAsetting for said governor whenever said change speed gear is in saidhigh speed driveA pition and a-low speed setting for said governorwhenever said change speed gear is Ain said low speed drive or saidneutral position. l

13. The arrangement as set forth in claim 12 in which the governor highspeed-setting and the governor low speed setting are proportional to thechange speed gear high speed ratio, and

the change speed gear low speed ratio.

